Question: $\left[\begin{array} {ccc} 0& 5& 6\\ -1& 1& 2\\ 3& 6& -3 \end{array}\right]$ What are the dimensions of the matrix?
Solution: The first dimension is the number of rows in the matrix. There are $3$ rows. The second dimension is the number of columns in the matrix. There are $3$ columns. In conclusion, the dimensions of the matrix are $3\times 3$.